While the majority of Albion's Scout Rifles use 7.78 mm bullets, the "Wave of Light" employs special .300 Blackout bullets. The Blackout got its name from the flash of light that occurs when the firing pin strikes the detonator. Despite its high lethality, this flash made it impractical for night operations. The risk of being detected by the enemy was simply too high.
However, that drawback was mitigated when combined with the "Wave of Light," as the weapon initially reacted with Arche, emitting light waves that were discovered to blind the enemy.